Buggy code:
public class FunctionChecker { private Logic logic ; private DataBase dataBase ; protected FunctionChecker ( Logic logic , DataBase dataBase ) { } protected InputException addTaskChecker ( String title ) { } protected InputException addEventChecker ( String title , String startDate , String startTime , String quantity , String timeUnit ) { } protected InputException addEventLessChecker ( String title , String fuzzyTime , String quantity , String timeUnit ) { } protected InputException addDeadlineChecker ( String title , String endDate , String endTime ) { } protected InputException addDeadlineLessChecker ( String title , String fuzzyTime ) { } protected InputException addRecurringEventChecker ( String interval , String title , String startDate , String startTime , String quantity , String timeUnit ) { } protected InputException addRecurringEventLessChecker ( String interval , String title , String fuzzyTime , String quantity , String timeUnit ) { } protected InputException addRecurringDeadlineChecker ( String interval , String title , String endDate , String endTime ) { } protected InputException addRecurringDeadlineLessChecker ( String interval , String title , String fuzzyTime ) { } protected InputException remindBefChecker ( String title , String quantity , String timeUnit ) { } protected InputException addRemindBefChecker ( String quantity , String timeUnit , String [ ] arg ) { } protected InputException remindChecker ( String title ) { } protected InputException forwardChecker ( String title , String quantity , String timeUnit ) { } protected InputException postponeChecker ( String title , String quantity , String timeUnit ) { } protected InputException redoChecker ( String redostep ) { } protected InputException undoChecker ( String undostep ) { } protected InputException undoneChecker ( String title ) { } protected InputException removeRemindChecker ( String title ) { } protected InputException doneChecker ( String title ) { } protected InputException openChecker ( String path ) { } protected InputException saveChecker ( String path ) { } protected InputException invalidChecker ( ) { } protected InputException tabChecker ( String workplace ) { } protected InputException setRecurringChecker ( String title , Boolean status , String interval ) { } protected InputException labelChecker ( String title , String category ) { } protected InputException sortChecker ( String fieldName , String order ) { } protected InputException filterChecker ( String [ ] arg ) { } protected InputException searchChecker ( String [ ] arg ) { } protected InputException editChecker ( String title , String fieldName , String newValue ) { } protected InputException deleteChecker ( String title ) { } protected InputException resetChecker ( ) { } protected InputException exitChecker ( String [ ] arg ) { } protected InputException addRemindChecker ( String [ ] arg ) { } protected InputException indexChecker ( String type , String [ ] arg ) { } private InputException checkInView ( int [ ] index , String type , String [ ] arg ) { } private InputException typeCaseSwitcher ( String type , String taskname , String [ ] arg ) { switch ( type ) { case "EDIT" : return editChecker ( taskname , arg [ 1 ] , arg [ 2 ] ) ; case "DELETE" : return deleteChecker ( taskname ) ; case "LABEL" : return labelChecker ( taskname , arg [ 1 ] ) ; case "SET-RECURRING" : return setRecurringChecker ( taskname , true , arg [ 1 ] ) ; case "REMOVE-RECURRING" : return setRecurringChecker ( taskname , false , null ) ; case "REMOVE-REMIND" : return removeRemindChecker ( taskname ) ; case "POSTPONE" : return postponeChecker ( taskname , arg [ 1 ] , arg [ 2 ] ) ; case "FORWARD" : return forwardChecker ( arg [ 0 ] , arg [ 1 ] , arg [ 2 ] ) ; case "REMIND" : return remindChecker ( taskname ) ; case "REMIND-BEF" : return remindBefChecker ( taskname , arg [ 1 ] , arg [ 2 ] ) ; case "DONE" : return doneChecker ( taskname ) ; case "UNDONE" : return undoneChecker ( taskname ) ; default : <START_BUG> return new InputException ( ) ; <END_BUG> } } private Boolean noRepeat ( String title ) { } private Boolean validFuzzyDate ( String fuzzyDate ) { } private Boolean validFuzzyDateThree ( String fuzzyDate ) { } private Boolean validFuzzyDateTwo ( String fuzzyDate ) { } private Boolean validFuzzyTime ( String fuzzyTime ) { } private Boolean validTime ( String time ) { } private Boolean validInterval ( String interval ) { } private boolean validUnit ( String unit ) { } private Boolean validQuantity ( String quantity ) { } private boolean isInteger ( String s ) { } private boolean isFloating ( String title ) { } private boolean validOrder ( String order ) { } }

Fix:
return new InputException ( "UNKNOWN" , "UNKNOWN" ) ;